Add iOS functional test for invariant culture only mode. (#49057)

Contributes to #43865  

1. ./build.sh mono+libs -os iOS -arch x64 -c Release  
2. ./dotnet.sh build /t:Test src/tests/FunctionalTests/iOS/Simulator/InvariantCultureOnlyMode /p:TargetOS=iOS /p:TargetArchitecture=x64 /p:Configuration=Release

Author: MaximLipnin

src/tasks/AppleAppBuilder/Xcode.cs

@@ -120,21 +120,21 @@ public string GenerateXCode(
         var defines = new StringBuilder();
         if (forceInterpreter)
         {
-            defines.Append("add_definitions(-DFORCE_INTERPRETER=1)");
+            defines.AppendLine("add_definitions(-DFORCE_INTERPRETER=1)");
         }
         else if (forceAOT)
         {
-            defines.Append("add_definitions(-DFORCE_AOT=1)");
+            defines.AppendLine("add_definitions(-DFORCE_AOT=1)");
         }
 
         if (invariantGlobalization)
         {
-            defines.Append("add_definitions(-DINVARIANT_GLOBALIZATION=1)");
+            defines.AppendLine("add_definitions(-DINVARIANT_GLOBALIZATION=1)");
         }
 
         if (EnableRuntimeLogging)
         {
-            defines.Append("add_definitions(-DENABLE_RUNTIME_LOGGING=1)");
+            defines.AppendLine("add_definitions(-DENABLE_RUNTIME_LOGGING=1)");
         }
 
         cmakeLists = cmakeLists.Replace("%Defines%", defines.ToString());

src/tests/FunctionalTests/iOS/Simulator/InvariantCultureOnlyMode/Program.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Globalization;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Runtime.InteropServices;
+
+public static class Program
+{
+    [DllImport("__Internal")]
+    public static extern void mono_ios_set_summary (string value);
+    
+    public static async Task<int> Main(string[] args)
+    {
+        mono_ios_set_summary($"Starting functional test");
+
+        var culture = new CultureInfo("es-ES", false);
+        // https://github.com/dotnet/runtime/blob/main/docs/design/features/globalization-invariant-mode.md#cultures-and-culture-data
+        int result = culture.LCID == 0x1000 && culture.NativeName == "Invariant Language (Invariant Country)" ? 42 : 1;
+
+        Console.WriteLine("Done!");
+        await Task.Delay(5000);
+        
+        return result;
+    }
+}

src/tests/FunctionalTests/iOS/Simulator/InvariantCultureOnlyMode/iOS.Simulator.InvariantCultureOnlyMode.Test.csproj

@@ -0,0 +1,17 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <MonoForceInterpreter>true</MonoForceInterpreter>
+    <RunAOTCompilation>false</RunAOTCompilation>
+    <InvariantGlobalization>true</InvariantGlobalization>
+    <TestRuntime>true</TestRuntime>
+    <TargetFrameworks>$(NetCoreAppCurrent)</TargetFrameworks>
+    <MainLibraryFileName>iOS.Simulator.InvariantCultureOnlyMode.Test.dll</MainLibraryFileName>
+    <IncludesTestRunner>false</IncludesTestRunner>
+    <ExpectedExitCode>42</ExpectedExitCode>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="Program.cs" />
+  </ItemGroup>
+</Project>